21939524 has 12 divisors (see below), whose sum is σ = 38438400. Its totient is φ = 10957128.

The previous prime is 21939521. The next prime is 21939527. The reversal of 21939524 is 42593912.

It is an interprime number because it is at equal distance from previous prime (21939521) and next prime (21939527).

It is not an unprimeable number, because it can be changed into a prime (21939521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1517 + ... + 6795.

It is an arithmetic number, because the mean of its divisors is an integer number (3203200).

Almost surely, 2^21939524 is an apocalyptic number.

It is an amenable number.

21939524 is a deficient number, since it is larger than the sum of its proper divisors (16498876).

21939524 is a wasteful number, since it uses less digits than its factorization.

21939524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6322 (or 6320 counting only the distinct ones).

The product of its digits is 19440, while the sum is 35.

The square root of 21939524 is about 4683.9645600709. The cubic root of 21939524 is about 279.9469457302.

The spelling of 21939524 in words is "twenty-one million, nine hundred thirty-nine thousand, five hundred twenty-four".